S-100 Floppy Controller

I recently acquired an IMSAI 8080 which contained an un-identified floppy disk controller. I haven't been able to find any information on the web about this controller so I decided to reverse engineer it and post my findings. The only marking on the board is "PV-1001-C" in the trace etching on both the front and back of the board.

PCB Images

Here are photos of the front and back for the board. Click the photos for larger versions.

Schematics

The following schematics where hand traced from the actual PCB, so it possible that there are mistaked in the drawings. The board did not have an reference designators for the components so the first page of the schematic shows the layout of the board with the designators I assigned to the components.

Boot ROM

Other Documents

COM2502 UART: I have not been able to find a datasheet for the S2350 UART used on this board, but the COM2502 is similar in some ways so this is a good reference.

Byte Magazine February 1977: On page 36 of this issue there is an article named "Build This Economy Floppy Disk Interface". This article describes how to build an S100 bus floppy interface that uses the same UART as this controller, and uses the same drive that my system came with.